seo: optimize /docs/research for CTR (title, meta, FAQ, internal links)

[philip638]

CTR harvest — /docs/research

Before metrics (Search Console): 583 impressions, 1 click, avg position 16.3. Page ranks but the snippet isn't earning clicks.

Changes

• Rewrote title/meta description to front-load the primary query and state the concrete deliverable (whitepaper, IETF drafts, papers) without touching the URL/slug.
• Improved the H1 subtitle to answer the query directly.
• Added a 4-item FAQ block (with FAQPage JSON-LD) covering the whitepaper, protocol comparison, IETF drafts, and the social-structures paper — feeds AI Overviews.
• Added 2 contextual internal links from the "Further reading" callout to related posts (sociology-of-machines, AI networking terminology) and to Core Concepts.
• Regenerated the corresponding plain-text page (src/pages/plain/docs/research.astro) to match.

No body/substance rewrite — this is a targeted snippet-and-structure pass. All factual claims unchanged.

npm run build and npm run check:plain both pass.